Attached to his IVF pole of fluid and antibiotics, with his tongue out in concentration, the three-year-old runs the corridors of the Royal Children’s Hospital, bee-lining to the playroom with his sack of trains and planes.

This is a different boy to the one who, just a week ago, was face down in the shower, desperate for relief from yet another bout of severe vomiting and diarrhoea.

It is a heartbreaking routine that repeats every couple of months. Libby Middleton knows that as soon her son stops eating, gastro-like sickness will start and continue until Connor is so weak and dehydrated he needs admission to the RCH.

But this cycle is speeding up, and doctors are keen to cut the circuit before Connor keeps losing weight and his ability to fight infection is compromised.

The Ballarat boy was born with an uncommon form of Hirschsprung’s disease, affecting one in 25,000 children, where missing nerve cells in the last part of the bowel can’t tell it to contract or relax.

At age two he had the definitive repair for Hirschsprung’s called a “pull-through”, where the large intestines missing nerve cells were removed, and the healthy part connected to his bottom.

That should have solved the problem, but Ms Middleton said with the intestines playing a key role in the body’s immune response, Connor continued to suffer from gastro-like viruses.

“There are not many kids that have what he’s got, so it’s trial and error,” she said.

Colorectal surgeon Sebastian King said he expected Connor to outgrow the recurrent infections once he was able to control his bowels.

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